1. Field of the Invention
The present invention relates generally to independent suspensions of vehicles and, more specifically, to a variable rate anti-roll bar link for connecting a control arm of such a suspension to an anti-roll bar.
2. Description of the Related Art
Independent suspension systems, those in which the suspension system provides a separate mounting for each wheel, often incorporate a linkage between the frame and the suspension system to control the action of the system and to overcome the tendency of car bodies to lean on corners. This linkage often is referred to as an anti-roll bar, a stabilizer bar, an anti-sway bar, or a sway bar. A short linkage connects the anti-roll bar to the suspension via a control arm. This component often is referred to as an end link.
A typical independent suspension is shown in FIG. 1. Suspension 10 comprises anti-roll bar 12 connected to lower control arms 14 via end links 16. This suspension further comprises upper control arms 18 and springs 20. The control arms in turn are mounted at one end to the vehicle frame (not shown), and at the other end are connected to wheels 22 via a connecting assembly. As the wheels travel up and down, the control arms pivot with respect to the frame. The end links transmit all or part of this movement to the anti-roll bar, which in turn is transmitted to the opposite end link to the control arm on the other side of the vehicle, to resist rolling of the vehicle.
FIG. 2 shows a conventional end link 30, which typically comprises hollow barrel portion 32 terminating in means for connecting to the control arm and anti-roll bar (not shown) such as threads. As shown, barrel portion 32 at each end comprises internal threads 34 into which the threaded portion 36 of a rod end may be inserted, and in turn connected to the respective control arm and anti-roll bar. This conventional link results in a linear rate spring characteristic, that is, the force applied to the anti-roll bar increases proportionally to the relative movement of the opposing control arms, as shown in FIG. 8. The rate of change of force applied to the anti-roll bar with respect to displacement of the opposing control arms is constant. In certain applications it is desirable to have a nonlinear progressive rate spring characteristic, that is, an end link in which the force applied to the anti-roll bar does not increase proportionally with respect to the relative movement of the opposing control arms, as shown in FIG. 9. There, the rate of change of force applied to the anti-roll bar with respect to the displacement of the opposing control arms increases as the relative displacement increases.
Accordingly, it is a principal object of the present invention to provide an end link that results in a progressive rate spring characteristic.
It is another object of the present invention to provide an end link with an adjustable spring characteristic.